As usually sites have a number of pages and generally all these pages are constructed by the same design. Part of HTML code is repeated in different pages.
The program allows to create a template and to insert the fields in it. Generally, one template is enough for one project of site. It must be defined values (HTML code) for each field. The set of fields (Local Variables) is formed for one template and it must be defined the values of those set of fields (variables) for each page separately. As a result of building, all pages will be constructed for their publication in Internet. For modifying design or contents of a template (multi-repeated content), it is enough to change only one HTML code and this change will be reflected at once in all pages.
Also, the division of HTML code into several parts, gives an opportunity of quick find the necessary part of HTML code and make the changes in it. There are global variables and it is possible to place fragments of HTML code in them.